Regulating circuits having alternating current input and direct current output are well known. Such circuits are to be found, for example, in other patents in the name of the inventor herein, such as Canadian Pat. No. 1,038,033, issued Sept. 5, 1978, and Canadian Pat. No. 1,073,975, issued Mar. 18, 1980. A similar operating circuit having battery charging and surveillance operating characteristics, is found in the inventor's Canadian Pat. No. 1,111,104 issued Oct. 20, 1981. Generally, in all such circuits, the power regulating components of the circuit are to be found on the output side of the circuit transformer, which may be an autotransformer or an isolating transformer.
However, it is very often desirable to provide input circuits for the operating transformers in regulated voltage power supplies, where the transformer power throughput operating controls are installed in the primary side of the transformer. Such regulated power supplies may be of the sort taught in a co-pending application, Ser. No. 349,186, filed Feb. 17, 1982 in the name of the same inventor herein.
One purpose for placing the transformer throughput power control devices--generally, synchronous operating current control devices--in the primary side of the transformer, is that the devices may be relatively inexpensive, off-the-shelf devices which are intended for operation at ordinary line voltages of 120 or 240 volts. However, it may often happen that the regulating circuit is intended for use in circumstances where the input line voltage may not be 120 or 240 volts, but may be twice as high as those voltages, or more. Moreover, it is desirable whenever possible to provide mass production of input circuit arrangements for regulated voltage supply circuits, so that economies of scale can be realized, and so that less expensive, lower stressed devices may be used.
Accordingly, the present invention is such that an external tapping arrangement is provided in the primary side of the transformer, so that differing input voltages may be utilized without changing the circuit components and only requiring re-connection of the input circuit taps.
Moreover, the present invention provides circuits whereby the leakage flux of the primary windings of the transformer is substantially limited or precluded--by the provisions of bifilar wound primary winding sections--by which self-saturation of the primary winding is overcome. There is, therefore, greater control over the operation of the synchronous operating current control devices in the primary section, because there is less interference with the devices over their entire firing angle range.
Generally, synchronous operating current control devices which are used to control power throughput of a transformer in a regulated voltage supply device may be saturable core reactors, magnetic amplifiers or phase-angle fired silicon controlled rectifiers. All of such devices, of course, have a control coil or control input circuit, and are well known in the art. Exemplary of the prior art employing such synchronous operating current control devices are the patents mentioned above in the name of the present inventor. Another example is Van Gilder, U.S. Pat. No. 3,914,685, issued Oct. 21, 1975.
All such synchronous operating current devices are under control of voltage sensing circuits of the sort that are also discussed in the above mentioned patents in the name of the present inventor, and also as discussed in the aforementioned co-pending patent application. In all events, the control coils or control circuits for the synchronous operating current control devices, function to determine the period of conduction of the synchronous operating current control devices during each cycle of operation of the alternating current power source for the circuits.
The present invention is particularly achieved by the provision of primary windings on the transformer in at least two sections which are bifilar wound on a single core. Each such bifilar wound section of the primary winding has, of course, a polarity of winding. There are then provided a pair of like synchronous operating current control devices, the first of which is series connected to the first of the pair of bifilar wound primary windings in opposite polarity thereto; and the second of which is series connected with the second primary winding section in the same polarity therewith.
Each of the series connections of synchronous operating device and its respective primary winding section may be connected in series or parallel with other (or others) of the primary winding sections, so that each series connected synchronous operating device and primary winding section is equally stressed, either by being connected in parallel across the input voltage source, or in series across the input voltage source.
Moreover, the invention is equally applicable to single phase or multi-phase input circuits. Where multi-phase circuits are used, the primary windings of each phase are as discussed above, and as described in greater detail hereafter.
Obviously, therefore, input circuits for the transformers of regulated power supplies can be provided where the primary winding sections and the synchronous operating devices may be physically and electrically dimensioned for connection in, say, a 120 volt alternating current circuit; so that if the input voltage is 240 volts, the sections are in series, or with rated input voltage the sections are in parallel.
Thus, the stress on the circuit components can be equalized, and moreover the circuit components can be mass produced to operate a variety of input voltages.
Needless to say, the circuit components can be provided in greater numbers than a single pair for each phase, as required, in the event that higher input voltages must be provided for.